技巧解析:根据ip地址查交换机端口


KeyWords: ip address port interface map show cam arp cdp detail mac-address-table
在一个Cisco 交换网络中间,已知某台机器的IP地址,如何找出它连接到了哪台交换机的哪个端口上呢?最方便快捷的方法使使用CiscoWorks 2000 LMS网管软件的User tracking 功能,图形化界面,一目了然 。
假如没有这个软件,也可以使用以下手工分析方法来找出答案:
示例网络:核心交换机为6509(交换引擎SE用CatOS, MSFC运行IOS软件)
1. 找出该IP所对应的MAC地址:
通过查看系统的ARP缓存表可以找出某IP所对应的MAC地址 。由于ARP不能跨VLAN进行,所以连接各个VLAN的路由模块MSFC就是最佳的选择--一般它在每一个VLAN都有一个端口(interface vlan n),能正确地进行ARP解释 。
6509MSFC#ping 10.10.1.65
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.1.65, timeout is 2 seconds:
!!!!!
SUCcess rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms
6509MSFC#show arpin 10.10.1.65
Internet 10.10.1.65 2 0006.2973.121d ARPA Vlan2
通过以上命令,我们知道10.10.1.65的MAC地址是0006.2973.121d, 这是IOS设备的MAC地址表达方式,在CatOS中,应写为00-06-29-73-12-1d.
2.在交换机上找出MAC地址所对应的端口
6509SE> (enable) show cam 00-06-29-73-12-1d
* = Static Entry.= Permanent Entry. # = System Entry. R = Router Entry.
X = Port Security Entry $ = Dot1x Security Entry
VLAN Dest MAC/Route Des [CoS] Destination Ports or VCs / [Protocol Type]
---- ------------------ ----- -------------------------------------------
2 00-06-29-73-12-1d 9/41 [ALL]
Total Matching CAM Entries Displayed =1
这是不是说IP为 10.10.1.65的机器就接在端口9/41上呢?
不一定 。假如以下命令中显示该端口上只有一个活动的MAC地址,那么答案就是肯定的:
6509SE> (enable) show cam dynamic 9/41
* = Static Entry.= Permanent Entry. # = System Entry. R = Router Entry.
X = Port Security Entry $ = Dot1x Security Entry
VLAN Dest MAC/Route Des [CoS] Destination Ports or VCs / [Protocol Type]
---- ------------------ ----- -------------------------------------------
2 00-06-29-73-12-1d 9/41 [ALL]
Total Matching CAM Entries Displayed =1
假如该命令显示该端口上有多个活动的MAC地址,那么这个端口应该连接到别的交换机或HUB设备上,见下面的例子(查找IP为10.10.1.250所对应的交换机端口):
6509MSFC#ping 10.10.1.250
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.1.250, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
6509MSFC#show arpin 10.10.1.250
Internet 10.10.1.250 4 0009.6b8c.64ec ARPA Vlan2
6509SE> (enable) show cam 00-09-6b-8c-64-ec
* = Static Entry.= Permanent Entry. # = System Entry. R = Router Entry.
X = Port Security Entry $ = Dot1x Security Entry
VLAN Dest MAC/Route Des [CoS] Destination Ports or VCs / [Protocol Type]
---- ------------------ ----- -------------------------------------------
2 00-09-6b-8c-64-ec 3/11 [ALL]
Total Matching CAM Entries Displayed =1
6509SE> (enable) show cam dy 3/11
* = Static Entry.= Permanent Entry. # = System Entry. R = Router Entry.
X = Port Security Entry $ = Dot1x Security Entry
VLAN Dest MAC/Route Des [CoS] Destination Ports or VCs / [Protocol Type]
---- ------------------ ----- -------------------------------------------
1 00-03-e3-4b-06-80 3/11 [ALL]
1 00-08-02-e6-b0-cd 3/11 [ALL]
1 00-02-a5-ee-f2-4f 3/11 [ALL]
1 00-09-6b-8c-66-d6 3/11 [ALL]
1 00-09-6b-63-17-d9 3/11 [ALL]
1 00-0b-cd-03-ec-f5 3/11 [ALL]
1 00-09-6b-63-17-d8 3/11 [ALL]
1 00-08-02-e6-b0-c1 3/11 [ALL]
1 00-08-02-e6-b0-85 3/11 [ALL]

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